The Origins of Penicillin
Penicillin was the first antibiotic ever found and is considered a "miracle drug" that transformed medicine and greatly reduced the number of deaths from infection. Today, it’s used to treat everything from throat infections, meningitis, and syphilis. How did this drug come into being, and how does it work?
In 1928, Scottish physician Alexander Fleming came back from a relaxing holiday to find mould growing on a Petri dish of Staphylococcus bacteria. He noticed the mould seemed to be preventing the bacteria around it from growing. Fleming soon identified that the mould produced a self-defence chemical that could kill bacteria, and he named the chemical penicillin. However, after Fleming published his findings, his peers showed very little interest in his work, and combined with the difficulty to purify penicillin from the mould, he soon dropped the project.
The chemical formula of penicillin.
Penicillin as a drug did not come into being until nine years later in 1937, when Howard Florey and Ernst Chain uncovered Flemng’s research and assembled a team of scientists to work solely on the 'Penicillin Project'. After three years, they found a painstakingly slow and inefficient way that produced pure penicillin.
The researchers started a global search for strains of mould with higher yields of the chemical. Mary Hunt, an assistant at the lab, found a rotting cantaloupe melon at a local market. The mould produced six times more penicillin than Fleming’s original strain. Soon, the Allies would have more than enough penicillin to satisfy the needs of the armed forces.
An American war poster depicting a wounded soldier and a medic, informing the public of the benefits of penicillin.
Penicillin works by attaching to the cell wall of bacteria and preventing it from building itself. It prevents the molecules of the cell wall to link with each other, weakening it enough that osmotic pressure pushes water into the cell, forcing it to burst. The fragments of the broken cell wall activate enzymes that further destroy the contents of the cell membrane and cytoplasm, completely killing the bacteria.
Diagram shows how penicillin kills bacteria.
After just over 75 years of clinical use, it is clear that penicillin's initial impact was immediate and profound. Its detection completely changed the process of drug discovery, its large-scale production transformed the pharmaceutical industry, and its clinical use changed forever the therapy for infectious maladies. It has helped humanity take a large step forward in the eternal fight against disease.
